1. Field of the Invention
This invention relates to an optical apparatus having a line-of-sight detecting device arranged to detect a line of sight of the user of the apparatus, and more particularly to an optical apparatus having the function of starting a predetermined action on the basis of data relative to the detected line of sight of the user.
2. Description of Related Art
Among optical apparatuses having such a kind of line-of-sight detecting device, there is a known one, as disclosed in U.S. Pat. No. 4,109,145, which is arranged to time-serially detect the position of a line of sight of the user obtained within a viewfinder and, upon detecting that the line of sight has stayed at a specific index (visual mark) for a predetermined period of time or longer, start a function corresponding to the specific index.
Further, in an apparatus disclosed in WO 87/07479, the inside of a screen is divided into a plurality of areas, in which indexes corresponding to information of various kinds are respectively displayed in the form of symbols or words, and, upon detecting that a line of sight of the user has stayed at a specific index for a predetermined period of time or longer, a function which corresponds to the specific index is started. Thus, an index and a function are in a one-to-one correspondence.
During recent years, there have been proposed cameras capable of changing over the size of a photo-taking image plane by using a so-called line-of-sight input, i.e., an input indicating a stay of the line of sight of the user at a specific index. In such a camera, in response to the line-of-sight input to an index which is usually disposed on a liquid crystal display part within a viewfinder, the photo-taking image plane size is changed over, and the liquid crystal display part of the viewfinder is driven and controlled, according to the changed photo-taking image plane size, in such a way as to change also the size of an image plane display made on the liquid crystal display part of the viewfinder by masking and concealing all unnecessary parts of the image plane on the liquid crystal display part.
In cameras of the type using IX 240 film (Advanced Photo System.TM.), the size of a photo-taking image plane is selectable from among three different image plane sizes, i.e., an image plane size having an aperture area of 15.6 mm.times.22.3 mm and called a classic size (hereinafter referred to as the C image plane size), an image plane size having an aperture area of 15.6 mm.times.27.4 mm and called a high definition size (hereinafter referred to as the H image plane size), and an image plane size having an aperture area of 9.6 mm.times.27.4 mm and called a panorama size (hereinafter referred to as the P image plane size).
However, the conventional arrangement for time-serially detecting the position of the line of sight as mentioned above has presented the following problem. Even after the user has looked at an index disposed within a viewfinder and a predetermined action corresponding to the index has been performed, if the user further continues to look at the index, the same action corresponding to the index would unnecessary be performed once again.
For example, with the user wishing to have a change-over (or selecting) action on the C, H and P image plane sizes, in changing the image plane size by the user looking at a predetermined index disposed on the liquid crystal display part within the viewfinder, if the user happens to further continue to look or gaze at the predetermined index after the change-over (switching) of the image plane size is effected, the image plane size selected then would be switched to the next image plane size, since it is determined that the switching of the image plane size has been requested.
Therefore, since the switching of the image plane size is repeatedly performed if the user continues to gaze at the predetermined index, it would become impossible to switch the image plane size over to a size desired by the user.
In setting and canceling a photo-taking mode or photo-taking conditions of the camera by using the line-of-sight input, the process of setting and that of canceling likewise continuously change from one over to another. The mode and conditions are, therefore, also difficult to set and cancel as desired, like in selecting the image plane size.
Further, in a case where a line of sight of the user passes around an index, there arises another problem that a function corresponding to the index tends to be performed since it is determined by mistake that the user is looking at the index. More specifically, in changing over the image plane size by the user looking at an index provided on the liquid crystal display part within the viewfinder, if the line of sight of the user passes around the index, the image plane size would be changed over every time the line of sight is detected. Under such a condition, the image plane size tends to be changed over to a size which is not desired by the user.